Neurons, Synapses, and Signaling

Flashcards about neurons, synapses, and signaling.

How does a neuron transmit information?

A neuron receives information, transmits it along an axon, and transmits the information to other cells via synapses.

Presynaptic Cell

Transmits information from a presynaptic cell to a postsynaptic cell.

Glia/Glial Cells

Nourish or insulate neurons.

Three Stages of Information Processing

Sensory input, integration, and motor output.

Sensory Neurons

Transmit information about external stimuli.

Interneurons

Integrate (analyze and interpret) the information.

Motor Neurons

Transmit signals to muscle cells, causing them to contract.

Central Nervous System (CNS)

Where integration takes place; includes the brain and a nerve cord.

Peripheral Nervous System (PNS)

Carries information into and out of the CNS. Composed of bundled neurons that form nerves.

Membrane Potential

The difference in electrical charge across a plasma membrane.

Resting Potential

The membrane potential of a neuron not sending signals.

Action Potentials

Changes in membrane potential.

Sodium-Potassium Pumps

Use the energy of ATP to maintain K+ and Na+ gradients across the plasma membrane.

Gated Ion Channels

Open or close in response to stimuli.

Voltage-Gated Ion Channels

Open or close in response to a change in voltage across the plasma membrane of the neuron.

Graded Potentials

Changes in polarization where the magnitude of the change varies with the strength of the stimulus.

Action Potential

A massive change in membrane voltage.

Voltage-Gated Ion Channels

Opening or closing when the membrane potential passes a certain level called threshold

Refractory Period

A second action potential cannot be initiated.

Axon Diameter

The speed of an action potential increases with the axon’s diameter.

Myelin Sheath

Insulate axons, causing an action potential’s speed to increase

Nodes of Ranvier

Gaps in the myelin sheath where voltage-gated sodium channels are restricted.

Saltatory Conduction

Action potentials in myelinated axons jump between the nodes of Ranvier.

Electrical Synapse

Electrical current flows from one neuron to another through gap junctions

Chemical Synapses

A chemical neurotransmitter carries information between neurons

Direct Synaptic Transmission

Binding of neurotransmitters to ligand-gated ion channels in the postsynaptic cell.

Excitatory Postsynaptic Potentials (EPSPs)

Depolarizations that bring the membrane potential toward threshold.

Inhibitory Postsynaptic Potentials (IPSPs)

Hyperpolarizations that move the membrane potential farther from threshold.

Summation

Individual postsynaptic potentials can combine to produce a larger potential.

Mechanisms of Terminating Neurotransmission

Enzymatic breakdown and reuptake.

Metabotropic Receptor

Activates a signal transduction pathway in the postsynaptic cell involving a second messenger.